1. Field of Invention
The present invention relates generally to particle separation in flue gases produced by power generation furnace and boiler processes, and in particular to a new and useful method of supporting impact type particle separators within various furnace environments.
2. Description of the Related Art
Impact type particle separators are well known for use in combustion furnaces, and circulating fluidized bed boilers and/or reactors. Impact separators are also commonly referred to as concave impingement members or U-beams. U.S. Pat. Nos. 4,891,052, 4,992,085 and 5,343,830 describe conventionally supported impact type particle separators and their uses in greater detail.
Generally, a furnace will have an arrangement of U-beams for separating particles from flue gases. U-beams are normally not cooled, but can be. Instead, they are constructed of high alloy sheet metal with the chemical properties selected to maximize resistance to oxidation and to other corrosive gases commonly found in furnaces and fluidized beds. It is known, for example, to construct U-beams from type 310 stainless steel (nominally 25Cr-20Ni) sheet metal, among other austenitic materials steels and/or alloys when operating in temperatures in excess of approximately 1200.degree. F. Typically, the U-beams are suspended from structural members located above the furnace enclosure. The attachment devices are normally welded to the U-beams to provide means for supporting the weight of the U-beams.
In some applications, it is sometimes desirable to increase the gas temperature in the region of the U-beams in the circulating fluidized bed boiler and/or reactor to temperatures reaching or exceeding approximately 1750.degree. F. At temperatures of this magnitude, it is difficult to identify weld filler metals and processes that will produce weld deposits having sufficient strength, oxidation resistance and corrosion resistance to withstand the stresses produced by such an extreme environment.